Had the HK for over a decade, tried to like it, but never did. Same thing about the 308.
No matter what you do with it, it won't group better than 2-2.5 MOA. I've done a everything possible except for replacing the barrel. Trigger job, a scope that costs as much as the rifle, G3-SG1 stock, heavy duty bipod, match ammo, etc. Even installed a harmonics device to improve accuracy, apparently it's a gimmick.
Lack of rail, mags without the anti-tilt feature and of the JFK vintage. I don't have a LBV for the G3 mags.
Plus the whole contraption is just too heavy. With the stock extended, it's just right when you are prone but too long when you are not. The rifle is heavy, mags are heavy and ammo is heavy. It's all bulky.
Also I am deeply concerned about parts availability in the future.
I guess the only positive thing I can say about it, it never, ever jams. Not once in 15 years.